In a Long Term Evolution (LTE) system, a physical downlink control channel (PDCCH) is carried on a control channel element (CCE), and the PDCCH channel may be transmitted on {1, 2, 4, 8} CCEs according to a size of a downlink control indicator (DCI) on the PDCCH or a channel quality status. A function of the PDCCH includes indicating scheduling of a physical downlink shared channel (PDSCH). If both a PDSCH and a PDCCH corresponding to the PDSCH exist in a subframe n, for whether downlink data transmitted in the subframe n is correctly received, a user (UE) needs to feed back an acknowledgement (ACK)/a negative acknowledgement (NACK) through a physical uplink control channel (PUCCH) in a subframe (n+k) to an enhanced node B (E-UTRAN Node B, eNB), and then the eNB determines, according to the feedback from the UE, whether to perform retransmission. Herein, an uplink-downlink subframe correspondence between the subframe n and the subframe n+k is predefined.
In a current LTE system, a subframe length is 1 ms, each subframe consists of two timeslots (slot) of a 0.5-ms length, and a length of a transmission time interval (TTI) is 1 ms. All scheduling is performed in a minimum scheduling unit of TTI. A round trip time (RTT) is 8 ms. Because one PUCCH may be unable to carry all content, two PUCCHs are generally transmitted in one subframe, and the two PUCCHs are transmitted in two timeslots respectively.
To achieve a shorter RTT and a lower data transmission latency, a scenario is proposed in which a TTI length is set to 0.5 ms or less. When UE transmits a PUCCH, a length of one TTI is 0.5 ms or less than 0.5 ms. According to the conventional art, only one PUCCH can be transmitted in one TTI of a length less than or equal to 0.5 ms, and the one PUCCH transmitted in the one TTI may be unable to carry all content. Currently, no corresponding solution is provided for this problem. Therefore, a method for determining a PUCCH resource needs to be proposed to resolve the problem that one PUCCH in one timeslot cannot carry all content in a communications system.